Field of the Invention
The present invention relates to an imaging device and a reproducing device for an image that is based on two image signals having different lengths of accumulation periods output from a single imaging element.
Description of the Related Art
By simultaneously capturing a motion image and a static image by using a single camera, it is possible to enjoy a critical scene in a motion image as a static image while viewing a captured scene as a motion image. Further, by simultaneously capturing a normal framerate motion image and a high framerate motion image by using a signal camera, a particular scene of a normal framerate motion image to a slow-motion video of a high framerate motion image can be switched to enjoy it as a high quality production. As such, a use of an imaging device having two photoelectric conversion units of different light receiving efficiencies can provide an image that allows a viewer to perceive full of movement, which can significantly enhance a value of a captured image.
Japanese Patent Application Laid-open No. 2014-048459 proposes an imaging device that reads out a first image signal and a second image signal from two photoelectric conversion units having different light receiving efficiencies. Such a configuration allows for simultaneously capturing a motion image and a static image through a single capturing lens and simultaneously capturing a normal framerate motion image and a high framerate motion image.
In the technique of Japanese Patent Application Laid-open No. 2014-048459, however, the use of two image signals having different lengths of accumulation periods output from a single imaging element causes the following problems.
In the imaging device disclosed in Japanese Patent Application Laid-open No. 2014-048459, a capturing is performed such that the first image signal and the second image signal have the matched ending time of an accumulation period. In this case, the intermediate time between the starting time and the ending time of an accumulation period is different between the first image signal and the second image signal, which means that a timing of capturing an object may be different between both signals. In particular, when an object is moving, the position of an object on an image may be different between the first image signal and the second image signal.
Thus, when trying to use one of the first image signal and the second image signal to correct the other, this results in a problem of being unable to perform proper correction because of the different positions of an object on an image. Further, when a part of frame images of a video generated by using one of the first image signal and the second image signal is replaced with frame images generated by using the other, this results in a problem of an unnatural motion of an object during video reproduction as if there were missing frames.